-er ddd dde ddf ddm ddr dds de- ded dee def dem der des dfd dfe dff dfm dfr dfs dmd dme dmf dmm dmr dms drd dre drm drr drs dsd dse dsf dsm dsr dss ed- edd ede edf edm edr eds eed eee eef eem eer ees ef- efd efe eff efm efr efs em- emd eme emf emm emr ems erd ere erf erm err ers es- esd ese esf esm esr ess fdd fde fdf fdm fdr fds fed fee fef fem fer fes ffd ffe fff ffm ffr ffs fmd fme fmf fmm fmr fms frd fre frf frm frr frs fsd fse fsf fsm fsr fss m-f m-r mdd mde mdf mdm mdr mds med mee mef mem mer mes mfd mfe mff mfm mfr mfs mmd mme mmf mmm mmr mms mrd mre mrf mrm mrr mrs msd mse msf msm msr mss rdd rde rdf rdm rdr rds re- red ree ref rem rer res rfd rfe rff rfm rfr rfs rmd rme rmf rmm rmr rms rrd rrf rrm rrr rrs rsd rse rsf rsm rsr rss sdd sde sdf sdm sdr sds se- sed see sef sem ser ses sfd sfe sff sfm sfr sfs smd sme smf smm smr sms sr- srd sre srf srm srr srs ss- ssd sse ssf ssm ssr sss